The present invention relates to a chip-in glass fluorescent display panel having driving semiconductor elements incorporated in a vacuum envelope and, more particularly, to a structure for connecting a grid to a grid driving semiconductor element.
In a conventional chip-in glass fluorescent display panel having driving semiconductor elements incorporated in a vacuum envelope, each anode wire on a glass substrate is made of a thin aluminum film, and the anode wires and an anode driving semiconductor element are connected to each other by wire bonding. Since each anode wire consists of aluminum, wire bonding can be easily performed.
As shown in FIG. 6A, a grid 1 is supported on a glass spacer 3 and is fixed thereon with crystallized glass 16, thus forming a three-dimensional structure on a glass substrate 22. Each grid wire 4 made of a thin aluminum film is formed between the grid 1 and a grid driving semiconductor element 2. The grid 1 and the grid wires 4 are connected to each other through bonding wires 5 and so are the semiconductor element 2 and the grid wires 4.
Since an iron.nickel.chromium alloy is used as a material for the grid 1, wire bonding cannot be directly performed. Therefore, as shown in FIG. 6B, an aluminum coat 6 must be formed in advance on the surface of an end portion of each grid element by sputtering, ion plating, vacuum deposition, or the like so as to allow wire bonding.
As described above, in a chip-in glass fluorescent display panel having driving semiconductor elements incorporated in a vacuum envelope, the wire bonding method is used to electrically connect a grid and a grid driving semiconductor element to each other. However, in order to realize wire bonding with high reliability, it is essential that bonding be performed between elements of the same material. Therefore, an aluminum coat must be formed on the surface of an end portion of each grid element.
It is especially difficult to form an aluminum coat on a predetermined portion of each grid element of a grid used for a graphic fluorescent display panel, in consideration of handling of components and the like, because the grid is formed by etching a thin plate made of an iron.nickel.chromium alloy, resulting in a considerably high process cost.